This invention relates to a label-equipped web method and, more particularly, to a sheet or form wherein the label is die-cut from base stock constituting the sheet, held in place by a pressure sensitive adhesive-equipped release liner, and printed thereafter.
It has become increasingly desirable to provide sheets generally and business forms particularly of minimal thickness for ease in processing through computer printers, especially table top personal computers with associated printers. One approach to achieve this has been to die cut the form itself to provide a removable label. This art is well known for die cut labels generally in U.S. Pat. Nos. 3,914,483 and 4,246,058 and for business forms in U.S. Pat. No. 4,379,573.
However, with the processing of sheets such as business forms through printers and the subsequent converting of the connected forms into a roll or a zig-zag pack, there arises the possibility of the release liner becoming detached through the imposition of shear forces. This exposes the pressure sensitive adhesive on the now-exposed face of the sheet with many undesirable consequences. Further, the current trend of omitting adhesive along the edge of an attached member increases the possibility of undesirable detachment. Illustrative of this trend in the art is exemplified by U.S. Pat. Nos. 3,926,113; 4,526,405, 4,664,416 and 5,011,559. The drawbacks of the prior art are avoided by the invention.
According to the invention, the release liner is strongly adhered to the rear face of the larger label stock web along one or two edges of the release liner. This is accomplished by providing the above-mentioned edge or edges free of release material--which is normally a silicone. The absence of a silicone on the surface of the liner confronting the adhesive provides a band on the release liner where the adhesive between the liner and web can integrate the liner and web substantially permanently. When the web over the liner is perimetrically diecut to provide a label spaced slightly from the band, the label can be removed while the web and liner remain together. Thus, there is no exposed adhesive on the rear face to cause the label stock to undesirably adhere to some other surface or sheet.
It is known to provide a wider label stock web and diecutting it over a narrower release liner--as set forth as prior art in U.S. Pat. No. 4,627,994. However, the release liner did not have an edge band or bands lacking the release coating--so it could not achieve the strong bond to the label stock web. From there, the art workers went away from the idea of a silicone free band. Instead, they went to separately attached webs as in the invention of the '994 patent and subsequent U.S. Pat. Nos. 4,696,843 and co-owned 4,865,669 and 5,006,191.
The one teaching of adhering a release liner to label stock by omitting a release material is Japanese application No. 63-274975 but did this by having a full perimeter free of release material so that the color former-equipped liner was immobilized for duplication thereon of the information printed on the label.
In the preferred embodiment of the invention, the advantages of retaining the release liner on the label sheet along an edge are provided by applying a pattern of coatings on the web patch or ply constituting the release liner. More particularly, a web ply is first coated with a pattern of release material (such as a silicone) in a pattern so as to leave an uncoated edge. Alternatively, a web ply fully coated with release material may be overcoated along an edge or edges to blank-out the silicone.
Thereafter, the entire ply is overcoated substantially over its already coated face with pressure sensitive adhesive--especially on most of the uncoated or overcoated edge or edges. When performed continuously, it is possible omit the release coating from either a longitudinal band or a transverse band and thereafter coat with adhesive this area as well as the previously release coated area. When either a continuous ply, viz., elongated web, or patches severed from a continuous ply are applied to a form or other label carrier constructed of label stock, the adhesive band of the release liner web patch adheres strongly to the form, effectively preventing detachment or dislodgment during printing and/or subsequent handling.
More particularly, the liner patch remains "frozen" in place during the imposition of shear forces to it and/or the sheet. It will be appreciated that the sheet or web usually is subjected to a number of movements parallel to its plane. Any contact with the surface bearing the liner patch will result in a force parallel to the sheet plane. Irrespective of the direction of this force, i.e., longitudinal or transverse or a combination thereof, it is effectively resisted by the permanency of the band of adhesive union between the sheet and the liner patch.
Examples other than printing where the patch-equipped sheet can be subjected to shearing forces are bursting, zig-zag folding, convolute winding and just plain insertion into an envelope. Even further, it will be appreciated that there are a myriad of forces possible in further handling which, even though they are not strictly parallel to the plane of the sheet, have a component parallel to the sheet which again can be effectively resisted by the instant invention.
The details of the invention can be seen in the ensuing specification.